解:∵6mx^2+4nxy+2x+2xy-x^2+y+4
=(6m-1)x^2+(4n+2)xy+2x+y+4,其中不含二次项,
∴二次项系数6m-1=0,4n+2=0,
解得:m=1/6,n=-1/2
∴6m-2n+2
=6×1/6-2×(-1/2)+2
=1+1+2
=4
这里面的二次项有:6mx^2,4nxy,2xy,x^2,合并同类项
(6m-1)x^2+(4n+2)xy+2x+y+4
其中二次项系数要为0
所有m=六分之一
n等于负的二分之一
剩下的
6m-2n+2
=6×1/6-2×(-1/2)+2
=1+1+2
=4
解:这里面的二次项有:6mx^2,4nxy,2xy,x^2,合并同类项 ∵6mx^2+4nxy+2x+2xy-x^2+y+4
=(6m-1)x^2+(4n+2)xy+2x+y+4,其中不含二次项,
∴二次项系数6m-1=0,4n+2=0,
解得:m=1/6,n=-1/2
∴6m-2n+2
=6×1/6-2×(-1/2)+2
=1+1+2
=4
原式=(6m-1)x^2+(4n+2)xy+2x+y+4,
因不含二次项,所以:
6m-1=0, 4n+2=0;
m=1/6, n=-1/2;
所以:6m-2n+2=4
先合并同类项,然后二次项为零,得到6m-1=0,4n+2=0,然后答案就出来了。
6m-1=0
4n 2=0
原式等于4